[PATCH] KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions

[PATCH] KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions

[Fuad Tabba]

kvm_inject_el2_exception() writes ESR_EL2 for synchronous exceptions
but not for SError. enter_exception64() does not write ESR_ELx for any
exception type, so the constructed syndrome is dropped. A guest L2
hypervisor taking a nested SError observes stale ESR_EL2.

This affects both kvm_inject_nested_serror() and the EASE path in
kvm_inject_nested_sea().

Write ESR_EL2 for except_type_serror, matching except_type_sync.

Fixes: 77ee70a07357 ("KVM: arm64: nv: Honor SError exception routing / masking")
Reported-by: sashiko <sashiko@sashiko.dev>
Signed-off-by: Fuad Tabba <tabba@google.com>
---
 arch/arm64/kvm/emulate-nested.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index 22d497554c94..c2580d40197e 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -2750,6 +2750,7 @@ static void kvm_inject_el2_exception(struct kvm_vcpu *vcpu, u64 esr_el2,
 		break;
 	case except_type_serror:
 		kvm_pend_exception(vcpu, EXCEPT_AA64_EL2_SERR);
+		vcpu_write_sys_reg(vcpu, esr_el2, ESR_EL2);
 		break;
 	default:
 		WARN_ONCE(1, "Unsupported EL2 exception injection %d\n", type);
-- 
2.54.0.1136.gdb2ca164c4-goog

Re: [PATCH] KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions

[Marc Zyngier]

On Mon, 15 Jun 2026 14:11:16 +0100, Fuad Tabba wrote:
> kvm_inject_el2_exception() writes ESR_EL2 for synchronous exceptions
> but not for SError. enter_exception64() does not write ESR_ELx for any
> exception type, so the constructed syndrome is dropped. A guest L2
> hypervisor taking a nested SError observes stale ESR_EL2.
> 
> This affects both kvm_inject_nested_serror() and the EASE path in
> kvm_inject_nested_sea().
> 
> [...]

Applied to fixes, thanks!

[1/1] KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions
      commit: e2cb1f4578625e71f461d5c1ce70984193389cbb

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.